The instant invention relates to medication injecting apparatus and specifically to a hypodermic injection device which injects medication but which does not require piercing the skin of a patient with a hypodermic needle.
Known gas powered hypodermic devices generally utilize some form of pressurized gas containing cartridge which includes a frangible seal. The frangible seal must be broken to allow the gas to escape from the cartridge. Known devices provide for release of a gas charge from the cartridge which is immediately used to power a piston, thereby to expel a liquid medication from an ampule. In the event that the seal on the cartridge is not fully or completely broken during the piercing operation, the charge activating a plunger in the ampule may be of insufficient strength to fully expel the contents of the ampule or may be of insufficient strength to expel the contents of the ampule with sufficient force to pierce the skin of the patient.
Known non-invasive hypodermic devices utilize some form of very small orifice or bore which is located at the tip of the ampule through which the medication is expelled. Since the ampules are generally formed of a glass or ceramic material, the process used to form the orifice requires a great deal of position in making an extremely small bore through a crystalline substance. The minimum size of a bore which may be suitably formed in such material is generally larger than that which may be formed in a metallic substance. The formation of orifice in a non-metallic crystalline substance may result in the formation of such an orifice which injects a stream of larger diameter than is possible with a metallic orifice and which in turn creates potential for patient bleeding.
An object of the instant invention is to provide a non-invasive hypodermic device which has a two-stage gas delivery system.
Another object of the instant invention is to provide a non-invasive hypodermic device which has an ampule-enclosing shroud to provide a spaced apart relationship between the patient's skin and orifice means carried on an ampule.
A further object of the instant invention is to provide a non-invasive hypodermic device which may be easily operated with one hand.
Still another object of the instant invention is to provide a non-invasive hypodermic device which has reusable and/or replaceable expendable components.
A further object of the instant invention is to provide a non-invasive hypodermic injection device which includes a refillable ampule.
Another object of the instant invention is to provide an ampule for use in a non-invasive hypodermic device which utilizes a metallic hypodermic needle.
Yet another object of the instant invention is to provide a non-invasive hypodermic device which is simple in construction and is therefore relatively easy and inexpensive to fabricate and assemble and which therefore may be marketed in both reusable and disposable embodiments.